McKay Kirsty, Salter Tara L, Bowfield Andrew, Walsh James L, Gilmore Ian S, Bradley James W
Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, L69 3GJ, UK.
J Am Soc Mass Spectrom. 2014 Sep;25(9):1528-37. doi: 10.1007/s13361-014-0924-x. Epub 2014 Jun 4.
Plasma-based desorption/ionization sources are an important ionization technique for ambient surface analysis mass spectrometry. In this paper, we compare and contrast three competing plasma based desorption/ionization sources: a radio-frequency (rf) plasma needle, a dielectric barrier plasma jet, and a low-temperature plasma probe. The ambient composition of the three sources and their effectiveness at analyzing a range of pharmaceuticals and polymers were assessed. Results show that the background mass spectrum of each source was dominated by air species, with the rf needle producing a richer ion spectrum consisting mainly of ionized water clusters. It was also seen that each source produced different ion fragments of the analytes under investigation: this is thought to be due to different substrate heating, different ion transport mechanisms, and different electric field orientations. The rf needle was found to fragment the analytes least and as a result it was able to detect larger polymer ions than the other sources.
基于等离子体的解吸/电离源是用于常压表面分析质谱的一种重要电离技术。在本文中，我们对三种相互竞争的基于等离子体的解吸/电离源进行了比较和对比：射频（rf）等离子体针、介质阻挡等离子体射流和低温等离子体探针。评估了这三种源的常压组成及其在分析一系列药物和聚合物方面的有效性。结果表明，每种源的背景质谱均以空气成分为主，射频针产生的离子谱更丰富，主要由电离的水团簇组成。还可以看出，每种源对所研究的分析物产生不同的离子碎片：这被认为是由于不同的底物加热、不同的离子传输机制和不同的电场方向所致。发现射频针对分析物的碎片化作用最小，因此它能够检测到比其他源更大的聚合物离子。
